3D printing guarantees efficiency. Myth or not?

As a science-based method, LCA is an excellent tool to bust the myths that surround sustainability. In this monthly series, we look at some common sustainability ideas to see if they are myth or true. In today’s episode of Sustainability Mythbusters: Is 3D printing the efficiency miracle solution everyone says it is?

3D printing, known in industry as additive manufacturing, is often presented as extremely efficient. Indeed, since 3D printing means placing exact amounts of material exactly where they are needed, the savings in raw material utilisation can be tremendous. But does that necessarily mean that anything 3D printed is automatically “efficient”? Sustainability Mythbusters takes a look.

Additive Manufacturing And Its Promises

Additive manufacturing (AM) is the standard term (ASTM F2792) for a “process of joining materials to make objects from 3D model data layer by layer, as opposed to subtractive manufacturing methodologies, such as traditional machining”. This sets additive manufacturing in contrast to other manufacturing processes, where you start with a bigger lump of material that is chipped down. Some manufacturers claim up to 90% savings in material consumption with this technology.

In a previous article we’ve shown, quoting Jeremy Faludi, that the material savings definitely exist, but depend on the shape of the product, the need for additional supports during the fabrication, etc. However, that article considered 3D printing as a prototyping technique, which was the most common use back then. Nowadays, we are seeing the first examples of industrial AM, and we can assume that the best-adapted conditions are present.

AM also claims other advantages: the very fact that it saves on raw materials is said to automatically induce savings in upstream transport, pre-processing, and management of the chipped waste material. Design-wise, products can be made lighter, saving a lot during downstream transportation.

Investing In The Right Improvements

As with all new discoveries, there is a tendency to see 3D printing and AM as the solution to all our problems and to try to secure a better future by quickly replacing all outdated technology. And as with all new discoveries, there are reasons why the reality is not there yet.

Sure, AM saves on material consumption. But any LCA practitioner and product manager can confirm that material consumption is not necessarily the main driver for the environmental impact of a product. Energy consumption, for example, is often a much more significant driver. Particularly for high-tech products, the energy spent during the use phase can be highly dominant. Therefore, a reduction in the use of materials and associated impacts from transport and waste may not be your main improvement opportunity.

Furthermore, 3D printing generally requires a lot more energy than e.g. injection moulding, the most commonly used technology for mass-production of plastic parts. We saw this in a recent project with a footwear manufacturer who used 3D printing for part of the production process. The company was shocked to learn that the carbon footprint of their 3D-printed shoe was nearly 6 times higher than of the average running shoe on the market, just because the printers needed that much electricity. This example illustrates that the environmental benefits from 3D printing need to be quite large to compensate for the extra electricity consumption.

Taking Advantage Of Specific Applications

However, there are a number of situations where 3D printing and AM can make a difference.

In cases where raw material consumption is the dominating driver for impact, savings will necessarily be welcome. Printing parts from aluminium or titanium for example, which require tremendous amounts of energy to be produced, has excellent chances of providing a net gain. Even more if recycled material is used.

AM’s main potential lies, I believe, in its ability to produce parts that are impossible to produce with conventional technologies. This will provide advantages beyond the sustainability promises. Researchers and companies are already working on nano-printing electronic components, reducing the important energy cost needed for chip fabrication.

In the transport sector, where the weight of materials determines the energy burden at the use phase, the energy savings that could be realized by using light-weight components made with a lattice structure are enormous.

Figure 2: This 3D-printed lattice cube made from titanium weighs about the third of solid cube while maintaining the same mechanical characteristics. Image credits and rights: General Electrics.

3D Printing Guarantees Efficiency: Myth or Not?

Status: Myth

3D printing and additive manufacturing are efficient in certain situations. The relatively low energy cost of plastics and its main production process, injection moulding, make the old-fashioned process the most environmentally friendly option in many cases. However, with energy-intensive materials and for specific uses, 3D printing could provide important savings.

In other words, a 3D-printed casing for your smartphone probably does not have any advantages over a standard one, but a 3D-printed lightweight jet wing would.

But the story is still being written… New applications for additive manufacturing are still being developed, especially in the field of nano-manufacturing for the electronics industry. These new applications are expected to provide many advantages beyond energy savings, like an extended service life for products. So, let’s hope that in the near future I have to re-write this episode of Sustainability Mythbusters and conclude that the myth has become reality.

It's easy to make assumptions in sustainability. But is following 'common sense' getting you the results you really need?

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‘I believe companies and organisations need to make drastic changes in the way they do business. In my opinion, LCA is the best tool to help people focus on actually relevant changes. It can help companies steer in more sustainable directions without falling for obvious, but sometimes misleading, options.’

For PROSUITE, Pré helped develop a novel sustainability impact assessment method for technology, including social impact assessment and new sustainability metrics. This helps understand the effect of these hard-to-predict technologies.